Remove isValid() from public API.

* Remove isValid() from VendorManifest; rather,
  add(ManifestHal &&) will do the check.
* Make ManifestHal::isValid() private; its XML Converter
  and string parser will do the check.

Test: libvintf_test
Bug: 34620633
Change-Id: I3c8164e5856ac06eb6d79bb34e092ec2dec4e68e
diff --git a/test/main.cpp b/test/main.cpp
index 9781576..76f8acb 100644
--- a/test/main.cpp
+++ b/test/main.cpp
@@ -51,6 +51,9 @@
     bool isEqual(const CompatibilityMatrix &cm1, const CompatibilityMatrix &cm2) {
         return cm1.hals == cm2.hals && cm1.kernels == cm2.kernels;
     }
+    bool isValid(const ManifestHal &mh) {
+        return mh.isValid();
+    }
     VendorManifest testVendorManifest() {
         VendorManifest vm;
         vm.add(ManifestHal::hal("android.hardware.camera", ImplLevel::SOC, "msm8892",
@@ -174,18 +177,13 @@
 }
 
 TEST_F(LibVintfTest, IsValid) {
-    EXPECT_TRUE(ManifestHal().isValid());
-    EXPECT_TRUE(VendorManifest().isValid());
-
-    VendorManifest vm = testVendorManifest();
-    EXPECT_TRUE(vm.isValid());
+    EXPECT_TRUE(isValid(ManifestHal()));
 
     ManifestHal invalidHal = ManifestHal::hal("android.hardware.camera", ImplLevel::SOC, "msm8892",
             {{Version(2,0), Version(2,1)}}, Transport::PASSTHROUGH);
-    EXPECT_FALSE(invalidHal.isValid());
+    EXPECT_FALSE(isValid(invalidHal));
     VendorManifest vm2;
-    add(vm2, std::move(invalidHal));
-    EXPECT_FALSE(vm2.isValid());
+    EXPECT_FALSE(add(vm2, std::move(invalidHal)));
 }
 
 TEST_F(LibVintfTest, VendorManifestGetHal) {